Catherine Rampell: Alan Krueger’s minimum wage research was remarkable. So was his happiness work.

FILE- In this Nov. 29, 2011, file photo Alan Krueger, chair of the White House Council of Economic Advisers, gestures during the daily news briefing at the White House in Washington. Princeton University Professor Krueger, a groundbreaking economist who served as a top adviser, has died according to a statement by the university. (AP Photo/Carolyn Kaster, File)

When I first learned of Princeton University economics professor Alan Krueger's tragic passing over the weekend, I thought about happiness.

Sure, most people would probably associate this intellectual giant and longtime public servant with his work on the minimum wage. In a paper looking at cross-state labor markets, he upturned decades of conventional wisdom that said raising the minimum wage would necessarily reduce employment. His finding that a higher wage floor could actually increase jobs for low-wage workers has become a staple of Econ 101 syllabuses.

Or perhaps people think of his work exploiting strokes of luck (season of birth, Vietnam draft numbers) to reveal how randomly assigned additional schooling could affect earnings. These and other pioneering papers — which inspired an entire generation of economists to look for similar “natural experiments” — probably would have won him (and his co-authors) a Nobel Prize in the coming years.

Or maybe you've heard about the rock-star job he did as chair of President Barack Obama's Council of Economic Advisers. Or the rock-star job he did studying, well, rock stars.

Or some of the other eclectic, off-the-beaten-path subjects that his omnivorous curiosity led him to, including: terrorism, the gig economy, Super Bowl tickets, offshoring, the digital divide or the relationship between income inequality and mobility (which he popularized as "the Great Gatsby Curve").

But, for me, his happiness research was top of mind. The cause of his passing hadn't yet been made public; in retrospect, maybe I wanted to think about this sunny stretch of research to keep from entertaining the dark possibility that his sudden death at 58 might be because of suicide, as his family would later confirm. Or maybe I was just thinking about it because it was the subject of one the last major assignments he gave me more than a decade ago, when I was his undergraduate research assistant.

Stories of Alan's fundamental decency are legion, but let me personally attest: He was a terrific and unpretentious boss.

In fact, it was not until my junior year or so — when he invited me along to a TV interview — that I grasped what a big shot I was working for (and that perhaps I should stop showing up to his office in my ratty Snoopy-themed sweatpants). I cringe to recall, as a nobody 19-year-old, scribbling (likely unsolicited) suggestions in red pen across an op-ed he was drafting. But he was not the type to throw his weight around. I think he just laughed. He may have even used my suggestions.

In the years since, Alan served as a mentor, friend and generous advocate. In many ways, I owe my journalism career to him — not least because he suggested me when he heard the New York Times was expanding its economics coverage as the financial crisis erupted.

So why, all those years ago, was Alan studying happiness, a topic that usually falls under the fiefdom of psychology, not the dismal science?

I don't know whether Alan felt he had a personal stake in the subject; right now, it's hard not to wonder, though he never said anything to me indicating this was the case. Then, as now, the research looked mostly like the perfect microcosm of what made Alan's scholarship so remarkable: That is, it was clever, resourceful, interdisciplinary, unorthodox and, most of all, public-spirited.

Working with a team of elite psychologists, Alan measured what conditions and activities make people happy (both in the moment and in retrospect). He was interested in why lottery winners, paraplegics or others who experience a sudden change in life circumstances often returned to their previous levels of contentment. And how much cultural norms affected self-reported levels of happiness. (Are the French actually more miserable than Americans?)

To some economists, investigating happiness probably seemed silly. But Alan saw it as a central mission of his discipline. The whole point of economics is to figure out how, in a world of scarce resources, we can make people’s lives better. And how is that possible without investigating and measuring their well-being — not their wages or the stuff they buy, but whether they are happy? Efficiency, gross domestic product, other “traditional” economic metrics — these were at best intermediate goals, or imperfect proxies, for the overarching objective of human welfare. And Alan always had his eyes on this prize.

Alan found creative ways not only to study important problems but also to evangelize his findings. At one point, when academic-research-as-metaphor-for-the-human-condition looked like a trendy Broadway genre, Alan and I even discussed writing a play inspired by his happiness work.

The play never got off the ground, alas. But the plan was quintessential Alan: He was a scholar motivated to use every tool in his kit to leave the world a bit better than he found it. And for all the heartache those who loved him are now suffering, that's what he did.

Catherine Rampell

Catherine Rampell’s email address is crampell@washpost.com. Follow her on Twitter, @crampell.